The present invention broadly relates to processing cyclic analog signals in communication systems, and deals more particularly with a device for converting the time base of the signals for the purpose of reading out data signals from a demodulator or the like, to a related communications system at the system clock rate.
Communication systems typically employ demodulators for demodulating analog signals which are subsequently processed by analog circuits to readout the communications data from the demodulator. For example, an FDM (frequency division multiplexed) signal may be demodulated into a TDM (time division multiplexed) signal by an analog processing circuit having frequency sweep and analog dispersion sections which convert the FDM signal into a cyclic signal consisting of a series of pulse segments. Each pulse segment corresponds to a communication channel and includes a plurality of pulses conveying information on that channel. It is often desired, however, to employ these demodulators in computer based signal processing systems having a time base which is different from that of the demodulator.
Analog processing circuits of the type mentioned above typically include analog components whose operating characteristics vary with changes in temperature; these changes in temperature result in alteration of the relative timing of the pulse segments output by the demodulator.
The foregoing factors involving timing differences between systems and undesired changes in signal timing within a system, render these demodulators relatively incompatible with many types of communications systems, and especially those employing digital type signal processors. It would therefore be desireable to normalize the relative timing rate of the pulse segments output by the demodulator so that they can be read out at a constant rate, and it would also be desireable to be able to read out these signals at the clock rate of a digital signal processing system.